Blossom-End Rot

Blossom-end rot is often misidentified as a fungal problem when it is actually a cultural (environmental) problem. Blossom-end rot occurs when the plant is unable to absorb and utilize calcium from the soil. The result is fruits, such as tomato, pepper, and squash look squishy and sunken on their blossom ends (opposite the stem.) Because the area is damaged, fungi will often appear as a side effect attacking the weakened fruit.

Environment:
There are several reasons why calcium may become unavailable to plants. Most often it is due to irregular soil moisture levels. Calcium is readily available when the soil is kept evenly moist. Allowing the soil to repeatedly dry out and then soak it, will prevent calcium uptake. Other causes of blossom-end rot are highly acidic soil, clay soil, salty soil, and root damage.

Management:
Lime and gypsum will add calcium to the soil. Mix these into the bed and maintain a steady moisture level to prevent blossom-end rot. You can ensure a balanced moisture level by mulching your vegetables after planting them in well-drained, raised beds. The raised beds will also help leach salts if the water you use is high in salts, just be sure to water deeply for adequate leaching.

When deciding which amendment to use, gypsum or lime, consider the pH of the soil. If the pH is highly acidic, lime will help raise the pH to neutral, adding calcium and enabling uptake. If the soil is high in clay this will reduce root development and reduce calcium absorption. To break down the clay amend the soil with gypsum.

| List of Diseases | Elimination of Pathogenic Disease Elements |
| Controlling Existing Pathogenic Diseases |